/**
* Licensed to Jasig under one or more contributor license
* agreements. See the NOTICE file distributed with this work
* for additional information regarding copyright ownership.
* Jasig licenses this file to you under the Apache License,
* Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a
* copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on
* an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.jasig.portal.jpa.cache;
import java.io.Serializable;
import java.util.Deque;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;
import java.util.Map.Entry;
import java.util.concurrent.atomic.AtomicInteger;
import javax.persistence.EntityManager;
import net.sf.ehcache.Ehcache;
import net.sf.ehcache.Element;
import org.jasig.portal.jpa.AbstractEntityManagerEvent;
import org.jasig.portal.jpa.EntityManagerClosingEvent;
import org.jasig.portal.jpa.EntityManagerCreatedEvent;
import org.jasig.portal.utils.cache.CacheKey;
import org.jasig.portal.utils.cache.SimpleCacheEntryTag;
import org.jasig.portal.utils.cache.TaggedCacheEntryPurger;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.ApplicationListener;
import org.springframework.stereotype.Service;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
/**
* Assumes only one {@link EntityManager} per {@link AbstractEntityManagerEvent#getPersistenceUnitName()} can be active
* per thread.
*/
@Service
public class EntityManagerCacheImpl implements ApplicationListener<AbstractEntityManagerEvent>, DisposableBean, EntityManagerCache {
private static final String CACHE_TAG = "entityManagerId";
private static final String CACHE_KEY_SOURCE = EntityManagerCacheImpl.class.getName();
//Thread local map of PersistenceUnit name to the Stack of EntityManagerIds
private static final ThreadLocal<Map<String, Deque<String>>> CURRENT_ENTITY_MANAGER_SESSIONS = new ThreadLocal<Map<String,Deque<String>>>();
//Map of PersistentUnit names to current open EntityManager count
private static final LoadingCache<String, AtomicInteger> OPEN_EM_COUNTER = CacheBuilder.newBuilder()
.build(new CacheLoader<String, AtomicInteger>() {
@Override
public AtomicInteger load(String key) throws Exception {
return new AtomicInteger();
}
});
protected final Logger logger = LoggerFactory.getLogger(getClass());
private Ehcache contentCache;
private TaggedCacheEntryPurger taggedCacheEntryPurger;
@Autowired
@Qualifier("org.jasig.portal.jpa.cache.EntityManagerCache")
public void setContentCache(Ehcache contentCache) {
this.contentCache = contentCache;
}
@Autowired
public void setTaggedCacheEntryPurger(TaggedCacheEntryPurger taggedCacheEntryPurger) {
this.taggedCacheEntryPurger = taggedCacheEntryPurger;
}
@Override
public void put(String persistenceUnitName, Serializable key, Object value) {
final Map<String, Deque<String>> currentEntityManagers = CURRENT_ENTITY_MANAGER_SESSIONS.get();
if (currentEntityManagers == null) {
logger.error("There is no currentEntityManagers Map in the ThreadLocal, no EntityManager scoped caching will be done. persistenceUnitName=" + persistenceUnitName + ", key=" + key, new Throwable());
return;
}
final Deque<String> entityManagerIds = currentEntityManagers.get(persistenceUnitName);
if (entityManagerIds == null || entityManagerIds.isEmpty()) {
logger.error("Cannot access cache for persistent unit " + persistenceUnitName + ", it has no active EntityManager, no EntityManager scoped caching will be done. key=" + key, new Throwable());
return;
}
final String entityManagerId = entityManagerIds.getFirst();
final SimpleCacheEntryTag entityManagerIdTag = new SimpleCacheEntryTag(CACHE_TAG, entityManagerId);
final CacheKey cacheKey = CacheKey.buildTagged(CACHE_KEY_SOURCE, entityManagerIdTag, entityManagerId, key);
this.contentCache.put(new Element(cacheKey, value));
}
@Override
public <T> T get(String persistenceUnitName, Serializable key) {
final Map<String, Deque<String>> currentEntityManagers = CURRENT_ENTITY_MANAGER_SESSIONS.get();
if (currentEntityManagers == null) {
logger.error("There is no currentEntityManagers Map in the ThreadLocal, no EntityManager scoped caching will be done. persistenceUnitName=" + persistenceUnitName + ", key=" + key, new Throwable());
return null;
}
final Deque<String> entityManagerIds = currentEntityManagers.get(persistenceUnitName);
if (entityManagerIds == null || entityManagerIds.isEmpty()) {
logger.error("Cannot access cache for persistent unit " + persistenceUnitName + ", it has no active EntityManager, no EntityManager scoped caching will be done. key=" + key, new Throwable());
return null;
}
final String entityManagerId = entityManagerIds.getFirst();
final SimpleCacheEntryTag entityManagerIdTag = new SimpleCacheEntryTag(CACHE_TAG, entityManagerId);
final CacheKey cacheKey = CacheKey.buildTagged(CACHE_KEY_SOURCE, entityManagerIdTag, entityManagerId, key);
final Element element = this.contentCache.get(cacheKey);
if (element == null) {
return null;
}
return (T)element.getObjectValue();
}
@Override
public void onApplicationEvent(AbstractEntityManagerEvent event) {
final String persistenceUnitName = event.getPersistenceUnitName();
final AtomicInteger counter = OPEN_EM_COUNTER.getUnchecked(persistenceUnitName);
final String entityManagerId = event.getEntityManagerId();
if (event instanceof EntityManagerCreatedEvent) {
final int count = counter.incrementAndGet();
if (logger.isTraceEnabled()) {
logger.trace("CREATE " + count + " - " + entityManagerId + " " + Thread.currentThread().getName());
}
//Get/Create the currentEntityManagers Map
Map<String, Deque<String>> currentEntityManagers = CURRENT_ENTITY_MANAGER_SESSIONS.get();
if (currentEntityManagers == null) {
currentEntityManagers = new HashMap<String, Deque<String>>();
CURRENT_ENTITY_MANAGER_SESSIONS.set(currentEntityManagers);
}
//Get/Create the Deque of current entityManagerIds
Deque<String> entityManagerIds = currentEntityManagers.get(persistenceUnitName);
if (entityManagerIds == null) {
entityManagerIds = new LinkedList<String>();
currentEntityManagers.put(persistenceUnitName, entityManagerIds);
}
//Set the current EMiD for this PU
entityManagerIds.offerFirst(entityManagerId);
}
else if (event instanceof EntityManagerClosingEvent) {
final int count = counter.decrementAndGet();
if (logger.isTraceEnabled()) {
logger.trace("CLOSE " + count + " - " + entityManagerId + " " + Thread.currentThread().getName());
}
//Purge any cached data related to this entity manager
taggedCacheEntryPurger.purgeCacheEntries(new SimpleCacheEntryTag(CACHE_TAG, entityManagerId));
//Get the currentEntityManagers Map
final Map<String, Deque<String>> currentEntityManagers = CURRENT_ENTITY_MANAGER_SESSIONS.get();
if (currentEntityManagers == null || currentEntityManagers.isEmpty()) {
logger.error("Closing " + entityManagerId + " but there is no currentEntityManagers Map for this Thread", new Throwable());
}
//Get the Deque of current entityManagerIds
final Deque<String> entityManagerIds = currentEntityManagers.get(persistenceUnitName);
if (entityManagerIds == null || entityManagerIds.isEmpty()) {
logger.error("Closing " + entityManagerId + " but there is no entityManagerIds Deque for this Thread", new Throwable());
}
//Get the current EMiD for this PU
final String currentEntityManagerId = entityManagerIds.getFirst();
if (!currentEntityManagerId.equals(entityManagerId)) {
logger.error("Closing " + entityManagerId + " but the current EntityManagerId is " + currentEntityManagerId, new Throwable());
}
//Remove the current EMiD
entityManagerIds.removeFirst();
//If nothing else is tracked for this PU remove the deque
if (entityManagerIds.isEmpty()) {
currentEntityManagers.remove(persistenceUnitName);
}
//If nothing else is tracked for this thread remove the local
if (currentEntityManagers.isEmpty()) {
CURRENT_ENTITY_MANAGER_SESSIONS.remove();
}
}
}
@Override
public void destroy() throws Exception {
for (final Entry<String, AtomicInteger> entityManagerCountEntry : OPEN_EM_COUNTER.asMap().entrySet()) {
final AtomicInteger counter = entityManagerCountEntry.getValue();
final int count = counter.get();
if (count > 0) {
final String persistenceUnit = entityManagerCountEntry.getKey();
logger.error("PersistenceUnit {} has {} EntityManagers that were opened but never closed", persistenceUnit, count);
}
}
}
}